1. Field of the Invention
The present invention relates to a wheel suspension for road vehicles, and more particularly to a rear wheel suspension having an arm called a trailing arm.
2. Description of the Relevant Art
There are known rear wheel suspensions comprising a trailing arm extending substantially in the fore-and-aft or longitudinal direction of a vehicle body in such known suspensions, the trailing arm has a front end pivotally mounted on a vehicle frame and a rear end supporting a rear wheel. Also, such suspensions are known to further comprise a guide means for guiding the trailing arm to control movement thereof laterally of the vehicle body while allowing the rear end of the trailing arm to move substantially in the vertical direction. The guide means comprises a plurality of lateral links each having one end coupled to the vehicle frame and the other end to the trailing arm. Examples of such rear wheel suspensions are disclosed in U.S. Pat. No. 3,327,803 and British Pat. No. 2,087,322. Each of the disclosed suspensions has at least two lateral links spaced apart from each other in the fore-and-aft direction of a road vehicle for preventing the wheel from toeing in or out excessively as the wheel moves up and down.
It is preferable for the rear one of the two lateral links to be attached to the trailing arm adjacent to the rear end thereof. However, there have been problems with respect to the arrangement of the front lateral link, as described below: With the suspension shown in the above U.S. patent, the front lateral link and the trailing arm are coupled at a position remote from the front end of the trailing arm, but close to the rear end thereof. This arrangement is poor in resistance to changes in the toeing of the wheel which are caused by side forces imposed on the wheel by the road surface. Where, on the other hand, the front lateral link is coupled to the trailing arm on the front end thereof that is connected to the vehicle frame, as disclosed in the above British Patent, the front lateral link is required to be quite small, with the result that substantial cost and labor must be expended to maintain a desired accuracy and mechanical strength of the small front lateral link.